montana VLF

[VICTOR]

This the schematic an pcb.http://mikes.front.ru/impdf/montana.pdf

[kt315]

comment I read there.
Interesting schematic, likes Magnum, has much of original schematic decisions. The schematic, PCB layout. Done by Vladimir, 'Dimir'.

[6F22]

Anybody can to say...?

Fine circuit, thanks.
May be sound is present here? And why so the speaker don't burn?

[Lake]

This the schematic an pcb.http://mikes.front.ru/impdf/montana.pdf

Anybody built this detector?
I'm just wondering C7,C8, C17 near 4046-chips are they really millifarade?
Hard to fit this size capacitor to pcb...
What kind of coil this detector requires?
Any comments about the quality of the detector?

[rael]

All capacitors are 1 uF.
Original coil construction is designed as 20 Cm (8") "OO" head.
Metal detector work very well.
Attached schematic is traced from PCB of detector maked in Montana - Bulgaria.

[aft_72005]

Hi rael
Are you have instruction manual for Montana?
Best regards.

[rael]

Hi rael
Are you have instruction manual for Montana?
Best regards.

Hi aft_72005

Sorry, it het been never printed.

BRGDS

[Ultimate_Haze]

Hi

Hi,
I have saw one.Its some kind of tesoro remade in Bulgarian metter.
There is no manual.Its is produced.But in a homemade way.
))

[aft_72005]

Hi rael and Ultimate Haze
In osc. Section, it is used PLL.
Although Calculable . what was operating frequency ?
Best regards.

[amtech2005]

montana VLF

Montana was not original work and name . I read it was a modified circuit from an old vlf "electronic magazine project" . I am not sure but I think the "original" operating frequency was around 13 khz . A u.s. quarter at 8 inches with discrimination , but it must have some problems , because I saw this circuit several years ago and never heard anything again untill now . So , must not be very popular and maybe not good in difficult soil......Eugene

Also , I will look for a folder with 3 or 4 pdf files from 2007 on this Montana !!! I sure hope I can find it . One pdf file was not in english and it was about 6 or 7 pages and was all about building this Montana VLF. I hope my memory is working ? !!

[aft_72005]

Hi amtech 2005
Yes , only osc. and discriminate section seem as elector magazine vlf
metal detector published year 1981.
I built elector detector some years ago .original working frequency
Was 8.64 khz . I changed it, my detector worked with 4.2 kHz.
Pll osc. Was very stable. Because pll output frequency naturally hi stable.
Best regards.

[rael]

Hi,
amtech2005 is right. I don't remember operating frequency. Schematic is maked for repair purpose.

[aft_72005]

Hi rael
Are you know coil specification ?
Best regards.

[strujas]

Freq for this schematic is 18 khz i think.

[rael]

Hi aft_72005,

Coil specification is 18KHz.

Best regards.